A longtime custodian at Sassarini Elementary School in Sonoma was arrested early Friday on suspicion of touching a student's genitals while in a campus bathroom.

Richard Piskulic, 53, of Vallejo was booked into the Sonoma County Jail on Friday morning on suspicion of lewd acts on a minor and annoying or molesting a minor. Bail was set at $100,000.

School and Sonoma Valley District officials were notified at approximately 6 a.m. of the arrest, said Loyal Carlon, director of human resources for the 4,600-student district.

Carlon and Superintendent Louann Carlomagno met with teachers and staff at the Fifth Street West campus before school began Friday. Additional staff were called in to support students and employees, he said.

"Shock and surprise" described staff reaction to Piskulic's arrest, Carlon said.

"It's an emotional time for them," he said.

"It was someone they have known for a long time," Carlon added. "It's disbelief. This is an allegation at this point."

Piskulic has worked for Sonoma Valley District for more than 30 years, Carlon said. His title is senior custodian and he currently is the only janitor assigned to the campus. He works from midmorning when students are on campus until after they leave campus, Carlon said.

The incident under investigation surfaced Thursday evening when Sonoma police were notified of an allegation of sexual misconduct involving Piskulic and a male student. The student told his mother that the custodian had touched his genitals while he was in one of the school bathrooms.

Detectives from the Sonoma County Sheriff's Office were called into the investigation and interviewed both the student and his mother, according to the Sheriff's Office. Detectives interviewed Piskulic at his Vallejo home and he was arrested at 2:45 a.m. School officials were alerted at about 6 a.m.

"We have certainly been in close contact throughout the day with police and sheriff's deputies," Carlon said.

It was unclear late Friday whether more students might have been involved. "That is something they are looking at," Sonoma Police Chief Brett Sackett said. "At this time, we don't have any additional information that suggests yes or no."

Sackett said parents should provide a safe environment for kids to speak about concerns.

"I think it's important that the parents have an honest and open discussion with their kids about stranger danger, so to speak," he said. "Depending on the age of the children, that conversation can be different."

The district sent letters in sealed envelopes home with Sassarini students Friday afternoon, alerting parents to the arrest and offering tips on discussing the incident with children.

It was important to get information to parents as soon as possible, Carlon said. Teachers will address the issue Monday -- speaking with students about how to stay safe and communicate concerns to adults.

"I think we pull together pretty quickly to do the right thing," Carlon said. "I think we got on top of it as far as communication goes."

District officials are awaiting results of Piskulic's scheduled arraignment Monday before making a decision as to his work status, Carlon said.

Anyone with information about the incident is asked to contact the Sonoma County Sheriff's Office at 565-2121.